A growing body of evidence demonstrates that adolescents with life-threatening asthma often underestimate the severity of their episodes.
Asthma is a chronic pulmonary disease characterized by recurrent reversible airway obstruction, airway inflammation, and airway hyperresponsiveness.1,2 Environmental factors may be key to the promotion of airway inflammation, thereby initiating airway hyperresponsiveness.3 As the airways modulate smooth-muscle constriction and secretions accumulate, increased airway resistance results, with a decreased expiratory flow rate detected as decreased peak expiratory flow rate or forced expiratory volume in 1 second (FEV1). The work of breathing increases as resistance increases; gas exchange is compromised due to airway obstruction and ventilation-perfusion mismatching, resulting in hypoxemia, dyspnea, and an urgent need for high-quality medical intervention.4
Morbidity and mortality in asthma continue to increase, despite improved treatment, an enhanced understanding of the pathophysiology of asthma, and directed therapies. Adolescents 10 to 14 years of age and adults over the age of 50 years are especially vulnerable, with significantly greater mortality.5
Epidemiological studies6-8 identified the escalating mortality accompanying asthma and began to present a profile of individuals who are fatality prone. One of the contributing factors identified for increased risk of asthma death may be underestimating (perhaps as a result of reduced perception) asthma severity.9 Resistive loading techniques using targeted flow protocols have been used to discriminate among various perceptual sensations and perceived breathing difficulty in control subjects and those with asthma (at varying levels of severity). There is a growing body of evidence10 that, in adolescents with life-threatening asthma, reduced sensitivity to increased resistive loading may lead to underestimation or delayed perception of increased respiratory loads. The blunted perception of changes in airway resistance means that the individual is not warned that medical intervention is required; the patient may delay treatment until a medical emergency exists. Further, when questioned by parents and medical caregivers, patients may report that they are in a normal state of respiratory health when, in fact, respiratory status is declining.
Guidelines for the management of asthma rely heavily on the ongoing assessment of asthma symptoms.11 Parents and the child are routinely questioned regarding the childs recent lung health, infections, and use of medication. Thus, information conveyed to the clinician reflects the familys perception of how well controlled the childs asthma has been. Unfortunately, there are cases in which significant variances exist between perception and physiological/medical status. The accurate perception of asthma symptoms is vital to the overall management, control, and treatment of asthma.
The inability of the patient to perceive the changes accompanying asthma exacerbations accurately has been shown12 to increase asthma morbidity and the use of medical care services, to promote overuse or underuse of medications, and to contribute to death. Perceptual variances are known to exist. Hypersensitivity to mild exacerbations in lung function can promote overuse of bronchodilators, iatrogenic problems, and excessive reliance on the health care system. Thus, the cost of controlling asthma is inflated, individuals consume scarce medical resources when they are not truly needed, and the risk of adverse effects of medication is increased. There are also individuals who do not sense changes in airway function (hyporesponders). They delay medical treatment, thereby increasing the severity of the exacerbation or risking death due to severe asthma. This is the paradigm associated with individuals who have experienced near-fatal asthma exacerbations.
Studies12-15 have confirmed that variations in the accurate perception of changes in airway function contribute to asthma morbidity and mortality. Individuals with accurate perception are able to recognize small changes in airway function, initiate appropriate treatment, and manage their disease successfully. Not only does accurate perception contribute to better medical intervention and lower medical costs, it also promotes enhanced quality of life.
Despite all that is known regarding asthma perception and airway management, there are still patients who fail to perceive their respiratory status accurately and react accordingly. As a measure of changing lung function, routine monitoring of peak expiratory flow rate or FEV1 is advocated. Peak flow meters and other handheld asthma monitors that include expanded data collection (peak expiratory flow, FEV1, FEF25-75, etc) have been designed and used with some success by patients, but a complete clinical picture is lacking. This stems from the fact that a clinically acceptable method for documenting changes in pulmonary function should also relate perceived changes in lung function to morbidity or asthma risk. Accurate self-monitoring for asthma is essential if good asthma control is to be achieved. For these and other reasons, the Asthma Risk Grid (see Figure 1) was devised.16
The Asthma Risk Grid: red=danger zone; white=accurate-perception zone; blue=symptom-magnification zone. Adapted with permission from Allergy Asthma Proc.16
The Asthma Risk Grid uses measured peak exploratory flow rate on the horizontal axis and perceived peak expiratory flow rate on the vertical axis. Actual and perceived peak expiratory flow rate data values are converted to a percentage of the patients personal best peak expiratory flow; this mathematical convention allows for individual variances and group comparisons.
The Asthma Risk Grid provides a methodology for monitoring pulmonary function and asthma perception concurrently. By overlaying multiple subjective and objective data points on the grid, the user makes a pattern of perceptual accuracy evolve.
In prior trials, we have collected data from patients at least twice per day, 30 minutes following use of their inhaled bronchodilators. Typically, one measure is completed in the am and the other in the pm hours. Many handheld electronic asthma monitors will collect and store pulmonary function data for at least 30 days or longer. Some monitors allow the patient to enter their peak flow guess (comment) and save with the pulmonary function data. Alternatively, patients can track their data on a sheet of paper by recording peak expiratory flow and other pulmonary function indices and their estimate of peak expiratory flow along with date and time of the monitoring. This data can then be collected and plotted for each 30-day interval and compared to prior months. The patients usual best should be the value represented by the patients usual state of health and while on optimal medical and medication management.
The grid is depicted as nine rectangular areas representing three distinctive zones, with the white area representing the zone of accurate perception, red indicating the danger zone, and blue showing the zone of symptom magnification. Vertical and horizontal lines representing 50% and 80% of the patients personal best peak expiratory flow rates are indicated. These demarcation lines are based on the US National Heart, Lung, and Blood Institute (NHLBI) guidelines and represent the green (go) zone of 80% or more, the yellow (caution) zone of 50% to 80%, and the red (stop) zone of less than 50% peak expiratory flow rate; these NHLBI zones are indicated by color on many peak flow meters and incentive spirometers.11 The line of identity depicts perfect subjective-objective agreement, and 10% variance lines are shown on either side of the line of identity.
The accurate zone (white area) consists of boxes 1 and 5, in which compromise below 50% or 80% is recognized, and box 9, in which adequate function is correctly identified. The danger (red) zone is depicted by boxes 4, 7, and 8: clinically significant compromised lung function is not recognized by the patient. The patient in this area risks undertreatment of asthma, with a corresponding increase in asthma morbidity, mortality, and health care utilization. Boxes 2, 3, and 6 represent the symptom-magnification (blue) zone. The hyperresponse of patients in this area may promote excessive use of fast-acting (rescue) medications and inappropriate health care use.
The application of the Asthma Risk Grid may aid patients, family members, and clinicians in achieving a more precise clinical picture of asthma and self-care.
A key objective in asthma care is the promotion of effective self-management. This includes educating the patient and family concerning the pathophysiology of asthma, asthma triggers, correct and timely use of asthma medications, the need for ongoing monitoring, and other self-help issues. Written action plans are recommended to guide the patient and family in medication use, activity, treatment options, and the development of self-management skills. These guidelines may not achieve their desired intent, however, if the patient does not accurately sense changes in pulmonary status. This is where the Asthma Risk Grid fills a gap in the clinical management of asthma.
For patients experiencing symptom magnification, behavioral strategies can be implemented to reduce medication use, conserving health care dollars while maximizing the efficacy of the prescribed medical intervention plan. Further, once symptom magnification is understood by the patient, his or her activity patterns may change in favor of a more active lifestyle, which could contribute to an improved quality of life.
For individuals in the danger zone, careful attention should be focused on early recognition of asthma exacerbations, on devising an improved monitoring plan, on altering medication use, and on other strategies for limiting and/or removing potentially serious deficits in the individuals overall asthma-management plan. For individuals who are accurate perceivers, continued monitoring is advocated to ensure that the asthma-perception profile remains accurate.
The parents of children and adolescents with asthma bear a significant burden in effective asthma management.. The Asthma Risk Grid can provide parents with valuable, timely information to help them understand the true nature of the illness. The Asthma Risk Grid provides an additional dimension by evaluating perception and its contribution to asthma management. When all signs and symptoms are considered, better management can be practiced. One goal of asthma management is to reduce and/or alleviate swings in physiological status through the correct and timely use of medications, the avoidance of asthma triggers, and the provision of high-quality education. To optimize the patients adherence to the asthma-management plan, however, variances in respiratory sensation must be accounted for by the clinician. For hyper-
responders, attention should be directed toward more conservative use of medication, along with increased physical activity. For hyporesponders, the use of controller and preventive medications should be stressed, as well as liberal objective monitoring of pulmonary function. Pulmonary function indices should be immediately compared with the individuals typical best performance and pattern of change. Specific trigger values should be identified at which prescribed treatment regimens are initiated and monitored for efficacy. This may require the use of portable electronic peak flow meters or spirometers that have programmable trigger instructions and alerts defining specific steps to be taken.
It is important to recognize that asthma management varies from individual to individual and is likely to change as the individual matures, and as more is learned about the pathophysiology of the disease. For effective asthma management to exist, perception of changes in respiratory status is crucial. In the absence of accurate perception, knowledge of the direction and magnitude of perceptual variance is vital so that appropriate countermeasures can be devised and implemented.
Rick Carter, PhD, MBA, is chair of the Jiann-Ping Hsu School of Public Health, Georgia Southern University, Statesboro; Robert Klein, MD, is professor of pediatrics, Department of Pediatrics, Brown University, Providence, RI; and Gregory K. Fritz, MD, is chair and professor of child and adolescent psychiatry; Elizabeth L. McQuaid, PhD, is assistant professor of psychiatry; and Sheryl Kopel, MS, is research associate, Brown Medical School.
1. Allen S, Connolly M, Dyer C, Gosney M. Asthma guidelines. Thorax. 2003;58:735.
2. Busse WW, Lemanske RF Jr. Asthma. N Engl J Med. 2001;344:350-362.
3. Cullinan P, Newman TA. Asthma: environmental and occupational factors. Br Med Bull. 2003;68:227-242.
4. Carter R. The physiologic principles of oxygen delivery. In: Tiep B, ed. Portable Oxygen Therapy: Including Oxygen Conserving Methodology. Mount Kisco, NY: Futura Publishing Company; 1991:81-124.
5. Sly RM. Mortality from asthma. J Allergy Clin Immunol. 1988;82(5 Pt 1):705-717.
6. Sly RM. Changing asthma mortality. Ann Allergy. 1994;73:259-268.
7. Barriot P, Rioiu B. Prevention of fatal asthma. Chest. 1987;92:460-466.
8. Molfino NA, Slutsky AS. Near fatal asthma. Eur Respir J. 1994;7:981-990.
9. Rubinfeld AR, Pain M. Perception of asthma. Lancet. 1976;1(7965):882-884.
10. Kifle Y, Seng V, Davenport PW. Magnitude estimation of inspiratory resistive loads in children with life-threatening asthma. Am J Respir Crit Care Med. 1997;156:1530-1535.
11. National Asthma Education and Prevention Program Expert Panel Report 2: Guideline for the Diagnosis and Management of Asthma. Bethesda, Md: National Institutes of Health; 1997. NIH Publication No. 97-4051.
12. Fritz GK, McQuaid EL, Spirito A, Klein RB. Symptom perception in pediatric asthma: relationship to functional morbidity and psychological factors. J Am Acad Child Adolesc Psychiatry. 1996;35:1033-1041.
13. Zach MS, Karner U. Sudden death in asthma. Arch Dis Child. 1989;64:1446-1451.
14. Magadle R, Berar-Young N, Weiner P. The risk of hospitalization and near-fatal and fatal asthma in relation to perception of dyspnea. Chest. 2002;121:313-315.
15. Rubinfeld AR, Pain MC. Perception of asthma. Lancet. 1976;1(7965):882-884.
16. Klein RB, Walders N, McQuaid EL, Adams S, Yaros D, Fritz GK. The asthma risk grid: clinical interpretation of symptom perception. Asthma Allergy Proc. 2004;25(1):1-6.